A conventional metal-matrix composite may be incorporated with fine reinforcing material therein for strengthening its mechanical property.
However, the fine reinforcing material, once directly fed into a metal matrix, the fine particles due to Van der walls force existing among the particles, will cluster in the metal matrix mixed with the fine particles of the reinforcing material, thereby causing unhomogeneous dispersion of the fine particles in the matrix and deteriorating the property of a finished casting product therefrom.
Meanwhile, a fine reinforcing material of dry particulates is directly incorporated into a molten metal alloy such as an aluminum alloy, the dry fine particulate reinforcing material will easily fly over as effected by a convection hot air streamflow above the molten alloy to cause loss of the fed reinforcing material. Meanwhile, the feed rate for adding the fine reinforcing material into the matrix will be difficultly controlled.
By using a vortex agitator for refining a metal-matrix composite, gases may be directed into the molten metal solution which should be removed by a degassing operation before casting process. Re-melting the metal-matrix composite under high vacuum degree may remove partial gases in the composite. However, the molten metal solution has a high viscosity, thereby being uneasy to extract gases outwardly from the viscous molten solution.
It is therefore expected to invent an apparatus for well incorporating fine particulate reinforcing material into the metal matrix during its refining process, and also providing a reliable degassing means for efficiently removing gases in the composite product.